Highly efficient intramolecular addition of aminyl radicals to carbonyl groups: a new ring expansion reaction leading to lactams

1993 ◽  
Vol 115 (8) ◽  
pp. 3328-3329 ◽  
Author(s):  
Sunggak Kim ◽  
Goon Ho Joe ◽  
Jung Yun Do
Keyword(s):  
Ring Expansion ◽  
Carbonyl Groups ◽  
Highly Efficient ◽  
Aminyl Radicals ◽  
Ring Expansion Reaction

Unusual Ring-Expansion Reaction of Polyfluorinated Norbornenoxetanes

Synthesis ◽  
2007 ◽  
Vol 2007 (9) ◽  
pp. 1349-1354 ◽  
Author(s):  
Viacheslav Petrov ◽  
Will Marshall
Keyword(s):  
Ring Expansion ◽  
Ring Expansion Reaction

Synthesis and Ring Cyclization - Expansion - Contraction Reactions of Some New 2,2-Disubstituted Indan-1,3-diones and Related Compounds

2006 ◽  
Vol 59 (1) ◽  
pp. 59 ◽  
Author(s):  
Craig J. Roxburgh ◽  
Lee Banting
Keyword(s):  
Catalytic Hydrogenation ◽  
Pyridine Ring ◽  
Functional Group ◽  
Chemical Properties ◽  
Ring Expansion ◽  
Ring Structure ◽  
Side Reactions ◽  
The Third ◽  
Ring Expansion Reaction ◽  
Related Compounds

We have found that the hydrochloride of 2-phenyl-2-[2-(2-piperidyl)ethyl]-4,5,6,7-tetrahydroindan-1,3-dione 1 possesses marked analgesic activity (100% inhibition referenced to codeine) and report, as part of an extensive synthetic program, the synthesis of 38 new and structurally related compounds. Selective catalytic hydrogenation of the pyridine ring of 2-phenyl-2-[2-(2-pyridyl)ethyl]-indan-1,3-dione 2 yields the nine-membered nitrogen-containing heterocycle 6 by a novel ring cyclization–expansion reaction. The structural and functional group parameters required for this novel ring-expansion reaction have been extensively and thoroughly investigated through the synthesis of a series of structurally related compounds; principally by modification, substitution, and replacement of the various functionality contained within 2. In addition, we report the synthesis of a series of new 2-methyl-2-(ω-N-phthalimidoalkyl)-indan-1,3-diones 41, 45, and 53, two of which, like the parent 2-phenyl substituted indan-1,3-dione 2, also undergo a novel ring cyclization–expansion reaction to yield eight- and nine-membered nitrogen-containing rings. However, in these cases, further transannular reactions occur to produce the new 5,5- and 5,6-ring-fused nitrogen-containing heterocycles 44, 48 and 51, 52. Hydrazinolysis of the third, 2-methyl-2-(4-N-phthalimidobutyl)-indan-1,3-dione yields the new azepine-containing ring structure 56 by direct cyclization. Furthermore, some interesting and unexpected chemical properties of the final compounds, which include selective and non-selective pyridine-ring hydrogenations and a few unexpected side reactions, are described.

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